The United Nations is trying to free the world________the threat of war.

He tried to join the army but was ______ because of poor health.

Michael Jordan has failed over and over again in his life.And that’s ______ he succeeds.

I always prefer starting early , _____ leaving everything to the last minute.

In the bookshop, a reader asked the shopkeeper _______ A Brief History of Time (时间简史)was an interesting book.